Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by hepatic steatosis, excluding alcohol and other clear liver damage factors, including NAFL, nonalcoholic steatohepatitis (NASH), liver fibrosis, liver cirrhosis, and even liver cancer. NAFLD can progress from NAFL to NASH and then to cirrhosis, liver cancer,1 end-stage liver disease, or even liver failure.2 NAFLD has become the most common cause of chronic liver disease, an emerging public health problem with an increasing prevalence in China. The global prevalence of NAFLD is as high as 25%. The prevalence of NAFLD in China is 29.2% and continues to rise. With a deeper understanding of the disease, increasing evidence has shown that NAFLD is a group of highly heterogeneous diseases, which is closely related to metabolic dysfunctions such as insulin resistance (IR), central obesity, dyslipidemia, hypertension, and hyperglycemia. It is the manifestation of metabolic syndrome in the liver.3 In 2020, more than 30 experts from 22 countries officially issued an international expert consensus statement to change the name of NAFLD to metabolism-associated fatty liver disease (MAFLD).4 Whether to drink alcohol is no longer mentioned in the definition of MAFLD to avoid the possible diagnostic contradiction when alcoholic liver disease and MAFLD coexist. The new nomenclature highlights the central position of metabolic factors leading to liver fat deposition in MAFLD.
Since the prevalence of NAFLD and the mechanism of NAFLD progression are unclear, it is very important to clarify the potential mechanism of NAFLD in detail. According to the definition of “metabolism”, the latest name of the disease suggests that environmental factors are more important than genetic determinants. However, the interreaction of environmental and genetic factors that promote liver disease is unclear. The definition of MAFLD inevitably includes the presence of metabolite abnormalities. Although there is a possibility that environmental and genetic factors contribute to MAFLD, there is an orphan scenario that cannot be included in the scope of MAFLD, which is genetically acquired fatty liver disease (GAFLD) and hereditary hepatic steatosis without metabolic correlation. Fat accumulation, prevalence of NASH, and progression to advanced fibrosis are more likely to occur in patients with PNPLA3I148M gene mutation if there is no more severe IR.5 In addition, PNPLA3I148M gene variation plays an important role in lean patients with NAFLD with no Type 2 diabetes.6 This supports the concept that genetic variation may play a key role in lean NAFLD patients who may have GAFLD and do not meet the MAFLD criteria. Metwally et al. examined the relationship between copy number variations (CNVs) in exportin 4 (XPO4) with liver damage in MAFLD in a large co
{"title":"Update cognition of nonalcoholic fatty liver disease/metabolism-associated fatty liver disease","authors":"Weijun Gu, Yiming Mu","doi":"10.1002/cdt3.14","DOIUrl":"10.1002/cdt3.14","url":null,"abstract":"<p>Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by hepatic steatosis, excluding alcohol and other clear liver damage factors, including NAFL, nonalcoholic steatohepatitis (NASH), liver fibrosis, liver cirrhosis, and even liver cancer. NAFLD can progress from NAFL to NASH and then to cirrhosis, liver cancer,<span><sup>1</sup></span> end-stage liver disease, or even liver failure.<span><sup>2</sup></span> NAFLD has become the most common cause of chronic liver disease, an emerging public health problem with an increasing prevalence in China. The global prevalence of NAFLD is as high as 25%. The prevalence of NAFLD in China is 29.2% and continues to rise. With a deeper understanding of the disease, increasing evidence has shown that NAFLD is a group of highly heterogeneous diseases, which is closely related to metabolic dysfunctions such as insulin resistance (IR), central obesity, dyslipidemia, hypertension, and hyperglycemia. It is the manifestation of metabolic syndrome in the liver.<span><sup>3</sup></span> In 2020, more than 30 experts from 22 countries officially issued an international expert consensus statement to change the name of NAFLD to metabolism-associated fatty liver disease (MAFLD).<span><sup>4</sup></span> Whether to drink alcohol is no longer mentioned in the definition of MAFLD to avoid the possible diagnostic contradiction when alcoholic liver disease and MAFLD coexist. The new nomenclature highlights the central position of metabolic factors leading to liver fat deposition in MAFLD.</p><p>Since the prevalence of NAFLD and the mechanism of NAFLD progression are unclear, it is very important to clarify the potential mechanism of NAFLD in detail. According to the definition of “metabolism”, the latest name of the disease suggests that environmental factors are more important than genetic determinants. However, the interreaction of environmental and genetic factors that promote liver disease is unclear. The definition of MAFLD inevitably includes the presence of metabolite abnormalities. Although there is a possibility that environmental and genetic factors contribute to MAFLD, there is an orphan scenario that cannot be included in the scope of MAFLD, which is genetically acquired fatty liver disease (GAFLD) and hereditary hepatic steatosis without metabolic correlation. Fat accumulation, prevalence of NASH, and progression to advanced fibrosis are more likely to occur in patients with PNPLA3I148M gene mutation if there is no more severe IR.<span><sup>5</sup></span> In addition, PNPLA3I148M gene variation plays an important role in lean patients with NAFLD with no Type 2 diabetes.<span><sup>6</sup></span> This supports the concept that genetic variation may play a key role in lean NAFLD patients who may have GAFLD and do not meet the MAFLD criteria. Metwally et al. examined the relationship between copy number variations (CNVs) in exportin 4 (XPO4) with liver damage in MAFLD in a large co","PeriodicalId":32096,"journal":{"name":"Chronic Diseases and Translational Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cdt3.14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45987638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}